Measuring your every stride and heartbeat, the TomTom Runner Cardio Watch provides vital, cardio-specific stats for daily workouts and high-octane training regimens. This run-specific watch combines built-in heart rate monitoring with QuickGPSFix Technology. It"s a potent combination, which keeps you on pace for your next foot race by providing target heart rate, as well as measuring time, distance, and calories burned. Working indoors when it"s raining or freezing cold outside, the watch"s built-in accelerometer gives accurate readings on treadmills without the use of GPS. Incorporating innovative technology into your daily running routine, the watch"s built-in heart rate monitor frees you from annoying chest strap heart rate monitors. This high-accuracy heart rate monitor measures changes in blood flow in your wrist by shining light through the skin and detecting changes in reflection. To ensure its accuracy, TomTom tested this device alongside electrocardiography and determined it to be "extremely accurate" for light exercise and high-intensity use alike. The built-in intensity zones allow you to step up your game, one level at a time. Five intensity zones help you burn fat or improve speed and fitness goals by regulating your intensity each step of the way. In addition, this watch allows you to set target zones based on pace or heart rate, record laps based on time, distance, or user-defined settings, and race against your previous best performances. Bundled with the Runner Cardio Watch is a USB desk dock that connects to both PC and Mac. TomTom MySports Web Tool allows you to sync and share data online, as well as visualize your running route on a map (free download online). You can also export data in various file formats, including the popular . Fit for personal training and . GPX for GPS tracking.